Measurement of the wakefield attraction for dust plasma molecules

The interaction forces in a system of two single dust particles immersed in the space charge sheath of a plasma discharge has been investigated quantitatively. From different techniques the attractive force provided by the wakefield of the dust particles has been measured from direct laser manipulation of the single particles. Furthermore, a structural phase transition with hysteresis of this system from a vertically aligned dust molecule into a separated state has been observed. The forces, structures and the hysteresis have been explained by means of own previous plasma crystal models.